Barrier fabrics have diverse applications as protective industrial outerwear, lab coats, hospital gowns, drapes, household wraps, bandages, and other waterproofing materials. For such applications it is advantageous to provide a strong, breathable, drapable and hydrophobic fabric.
Numerous prior art patents disclose various textile materials which are impermeable to water and aqueous liquids but are permeable to air and moisture vapor. In general, the moisture permeable fabrics are porous structures coated with plastic film layers such as polyurethane, see U.S. Pat. No. 4,554,198 to von Blucher and U.S. Pat. No. 4,539,255 to Sato. Alternatively, waterproof fabrics, permeable to moisture, are also provided by coating a porous textile substrate with coagulated elastomers, typically long polymer chains or synthetic resins, see U.S. Pat. No. 4,537,817 to Guillaume.
U.S. Pat. No. 4,499,139 to Schortmann, discloses a porous barrier fabric comprised of plastic films having micropores formed by froth bubbles. The fabric is formed by microsizing a single ply hydroentangled nonwoven fibrous web with an aerated latex froth. Microsizing is defined in the Schortmann '139 specification "as the application of a latex froth to a fabric to create microsize pores, which are necessary to establish a bacterial barrier in a fabric while preserving air permeability". The barrier fabric structure has sufficient hydrophobicity to be a bacterial barrier while maintaining comfort, drapeability, air permeability, and flexibility.
The prior art has thus provided porous materials which are permeable to moisture vapor and impermeable to water and aqueous liquids. However, these materials are not suitable as barriers to air. There is a need in the art for a nonporous barrier fabric which is permeable to moisture but impermeable to air as well as to aqueous liquids.
Accordingly, it is a broad object of the invention to provide a nonporous barrier fabric comprised of a substrate sized with a film forming filler material, which is permeable to water vapor but acts as a barrier against airborne or aqueous transported contaminants, e.g. bacteria, viruses or blood.
A more specific object of the invention is to provide a method for producing breathable barrier fabrics which are less complex to manufacture and have improved properties over the prior art.
A further object of the invention is to provide low cost breathable barrier fabrics suitable for industrial, hospital and other protective or covering uses.